Re:HCl & residual chloride

     >Can you say more about the problem of residual chlorides? I am one of 
     >those fishkeepers who adds salt to my tank--1 tblsp/5 gallons. What 
     >happens to the chloride there? I don't know the chemical terms but 
     >get the impression from some chemist friends that residual chloride 
     >should be harmless ... TIA.
     Chloride IS harmless.  In the case of adding HCl to your tank, the 
     extra Cl should only be a few ppm.  Even in your case, the amount of 
     chloride would only be 
     1 tblsp=~10 grams NaCl
     5 gallons=18.9 liters
     10 g NaCl/18.9 liters=529 ppm NaCl, or 321 ppm Cl and 208 ppm Na 
     (based on its molecular weight; golly I hope I calculated this right!) 
     Marine organisms are exposed to much higher levels of chloride with no 
     ill effect.  Have no fear.